共查询到20条相似文献,搜索用时 31 毫秒
1.
Katsuhiro Niiro 《Transportation》1989,16(4):279-295
The number of bus passenger has been decreasing in Japan since 1969. The increase in car ownership and development in urban rapid rail network has deprived bus service of passengers. The bus industry has suffered from depression for the last twenty years. However, many bus routes are still operated commercially. The amount of external subsidies is not large. The industry is under strict regulation. The common way for bus operators has been to increase fares rapidly in order to keep their break even condition. The first half of the paper describes present circumstances of the bus industry in more details. Then the second half of the paper treats the estimation of the effect of each factor on bus demand by using pooled data in Japanese medium sized cities. The results suggest that the increase in car ownership has had a crucial effect on local public transport demand and is likely to continue to do so. 相似文献
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Nadia Magnenat‐Thalmann 《运输规划与技术》2013,36(4):275-279
The system described in this paper allows the user to visualize the Montreal transportation system. The user is provided with several different maps. The complete subway network and all regular bus lines have been included. The subway network and the bus lines can be selectively displayed. The most attractive feature of this system is the possibility of obtaining all possible routes between two different places. The input is based on the menu technique. The system can be easily adapted to other large urban transportation systems. 相似文献
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N80钢CO2腐蚀缓蚀剂筛选及性能评价 总被引:1,自引:0,他引:1
文中采用高温高压反应釜借助腐蚀挂片失重法测试了油田常用咪唑啉类和炔氧甲基季铵盐型两种不同类型的缓蚀剂在饱和CO2油田采出液对N80钢的缓蚀行为,分析了缓蚀剂的溶解、分散性,采用扫描电镜对腐蚀后表面形貌进行了观察。研究结果表明:在两种缓蚀剂中,炔氧甲基季铵盐型缓蚀剂溶解性高于咪唑啉型,而炔氧甲基季铵盐IMC-871GH1型缓蚀剂可以集优异溶解和分散性于一体。腐蚀形貌测试结果反映出缓蚀剂在材料表面均匀覆盖程度直接影响材料点蚀行为,添加炔氧甲基季铵盐型缓蚀剂试样表面致密度高于咪唑啉型缓蚀剂,点蚀倾向小。 相似文献
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《Transportation Research Part D: Transport and Environment》2001,6(3):221-227
The paper outlines the basic effects of aging and technological substitution of motor vehicles on their air emissions. The analysis is facilitated with the aid of an existing model that simulates the internal dynamics of vehicle populations and performs emission calculations. The renewal rate of vehicles is modeled and associated uncertainties are demonstrated. The sensitivity of the system to specific age and technological parameters is examined. The impacts of emissions deterioration, implementation of inspection and maintenance programs and introduction of cleaner fuels are studied. 相似文献
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The paper describes a new method of optimizing traffic signal settings. The area-wide urban traffic control system developed in the paper is based on the Bee Colony Optimization (BCO) technique. The BCO method is based on the principles of the collective intelligence applied by the honeybees during the nectar collecting process. The optimal (or near-optimal) values of cycle length, offsets, and splits are discovered by minimizing the total travel time of all network users travelling through signalized intersections. The set of numerical experiments is performed on well-known traffic benchmark network. The results obtained by the BCO approach are compared with the results found by Simulated Annealing (SA). It has been shown that the suggested BCO approach outperformed the SA. 相似文献
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《Transportation Research Part A: Policy and Practice》2001,35(7):601-623
The interaction between accessibility and rural development is a subject of current concern. The degree of accessibility determines the ability of individuals to participate in development and other social activities. The paper describes the development of a numerical method for quantifying accessibility-benefits suitable for application in developing countries. The methodology provides an integrated approach to analysing accessibility by considering all constraints faced by individuals, particularly their income. The method can be used to evaluate different accessibility-enhancing strategies, and to quantify the benefits derived by different groups of individuals under various states of socio-economic development in rural areas of developing countries. The application of the accessibility-benefits model is demonstrated using two hypothetical case studies featuring the effects of improving intermediate means of transport and improving temporal strategies. The purpose of the case studies is to demonstrate how different accessibility-enhancing strategies can be related to the key model parameters, and to show the likely magnitude of the benefits, in monetary terms, that can be attained by individuals with different income levels. 相似文献
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The long-term development of a mobile booking taxi application service depends on the continued use of its passengers. The aim of this study is to investigate the determinants of the mobile taxi booking application service’s continuance intention, using the technology continuance theory by including the perceived risk and subjective norms. The data were collected by surveying 387 users of the mobile taxi application service. The data were analysed by applying the partial least squares technique. The analysis showed that the technology continuance theory has extensive power to explain the continuance intention to use the mobile booking taxi application. Subjective norms also have a significant effect on the attitude of mobile booking taxi application users which represents an important contribution to technology continuance theory extension. The theoretical and practical significances of the study have been discussed. 相似文献
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《Transportation Research Part A: Policy and Practice》2003,37(2):109-127
This paper presents a procedure for dynamic design and evaluation of traffic management strategies in oversaturated conditions. The method combines a dynamic control algorithm and a disutility function. The dynamic algorithm designs signal control parameters to manage formation and dissipation of queues on system links with explicit consideration of current and projected queue lengths and demands. The disutility function measures the relative performance of the dynamic control algorithm based on preset system performance goals. The user may statically select the management strategy, or alternatively the system may be instructed to set off different management schemes based on predefined performance thresholds. The problem was formulated as one of output maximization subject to state, control, and traffic management strategy choices. Solutions were obtained using genetic algorithms. Four traffic management plans were tested to show the capabilities of the new procedure. The results show that the procedure is able to generate suitable signal control schemes that are favorable to attaining the desired traffic management goals. The results showed that multiple, or hybrids of single measures of effectiveness may need to be examined in order to correctly assess system performance. The procedure has potential for real-time implementation in an intelligent transportation system setting. 相似文献
14.
The objective of this paper is to contribute an empirical study to the literature on transportation impacts of Information
and Communications Technologies (ICT). The structural equation model (SEM) is employed to analyze the impacts of ICT usage
on time use and travel behavior. The sample is derived from the travel characteristic survey conducted in Hong Kong in 2002.
The usage of ICT is defined as the experience of using e-mail, Internet service, video conferencing and videophone for either
business or personal purposes. The results show that the use of ICT generates additional time use for out-of-home recreation
activities and travel and increases trip-making propensity. Individuals at younger age or with higher household income are
found to be more likely ICT users. The findings of this study provide further evidence on the complementarity effects of ICT
on travel, suggesting that the wide application of ICT probably leads to more, not less, travel. The study also demonstrates
the importance of considering the interactions between activity and travel for better understanding of the nature and magnitude
of the impacts of ICT on time use and trip making behavior. 相似文献
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大跨度高墩连续刚构桥是跨越深山沟或江河的一种广泛的结构形式,其地震作用下的响应与中小跨径混凝土梁桥有所不同,本文以福建省沈海复线福鼎贯岭至柘荣段桐山溪特大桥(104+200+104 m)为工程背景,采用有限元分析软件Midas/civil构建有限元模型,进行结构特征值分析及地震作用下的反应谱分析,得到桥梁在地震作用下的动力响应,并研究了双肢薄壁墩墩间联系梁对大跨度连续刚构桥抗震性能的影响。 相似文献
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《Transportation Research Part A: Policy and Practice》2007,41(5):411-427
The main goal of the research was to compare alternative methods of spatial transfer as a function of sample size. The study was based on the mobility surveys conducted in the Helsinki Metropolitan Area in 1995 and in the Turku region in 1997. The Helsinki Metropolitan Area data base was used to estimate the models that were to be transferred. The data base in the Turku region represents the application context to which the estimated Helsinki Metropolitan Area models are transferred. The transfer procedures examined were Bayesian updating, combined transfer estimation, transfer scaling, and joint context estimation procedures. To explore the impact of sample size on transferring performance, model transferability was tested using six different sample sizes. The model transferability was examined by comparing the transferred models to the models estimated using the entire set of the data which can be regarded as the best estimate representing “the real situation”. The results indicated that joint context estimation gives the best prediction performance in almost all cases. In particular, the method is useful if the difference in the true parameters between the two contexts is large or only some of the model coefficients are precise. The applicability of joint context estimation can be improved by viewing the coefficients as variable-oriented and emphasizing precise and imprecise coefficients differently. 相似文献
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The optimization model proposed in this paper is aimed to assist city councils (or other transport authorities) in the planning of integrated transit-parking policies. The objective is to minimize the joint operating deficit of the transit and parking operators while ensuring given minimum levels of (motorized) mobility in a city. The key decision variables are transit fares and parking fees. The impact of price changes on transit and car modal shares are described by logit functions of the generalized travel costs. The practical utility of the model is illustrated with a case study involving a midsize city in Portugal.
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Elvezia M. Cepolina Alessandro Farina 《Transportation Research Part C: Emerging Technologies》2012,21(1):230-243
The paper concerns the conceptual design of a transport system for pedestrian areas. The proposed transport system is based on a fleet of eco-sustainable Personal Intelligent City Accessible Vehicles (PICAVs). The vehicles are shared through the day by different users and the following specific services will be provided: instant access, open ended reservation and one way trips. Referring to the proposed transport system, a new methodology to optimise the fleet dimension and its distribution among the stations is proposed in this paper. The problem faced is an optimisation problem where the cost function to be minimised takes into account both the transport system cost and the user costs that depend on the waiting times. A random search algorithm has been adopted. Given a fleet dimension and its distribution among the stations, the waiting times of the users are assessed by a microscopic simulation. The simulation model tracks the second-by-second activity of each PICAV user, as well as the second-by-second activity of each vehicle. The overall methodology has been implemented in an object-oriented simulator. The proposed transport system has been planned and simulated for the historical city centre of Genoa, Italy. 相似文献